Standard millwork and cabinetry hardware, such as recessed hinges, are not designed for use in applications where component pieces are heavy, use is frequent, or where high security is required. In these cases and others, wear on the hinges and hardware causes the need for frequent replacement, maintenance and adjustment.
Hardware replacement, maintenance and adjustment are time consuming and often expensive. For example, adjustment is usually required in more than one dimension. If the application has two or more hinges, as is usually the case in heavy duty applications, adjustments must be carried out on each hinge.
The prior art is replete with hinge designs. However, most prior art hinges suffer from various disadvantages including difficulty of installation, fragility of components, complicated construction, and high manufacturing costs.
A hinge design that is typical of the prior art is shown in FIGS. 1A and 1B. Hinge cup 10 is pivotally connected to hinge body 12 by hinge arm 14 and hinge link 16. Hinge arm 14 and hinge link 16 are connected to the hinge cup and the hinge body by pins 11, 13, 15 and 18. Pins 11, 13, 15, and 18 are generally aligned parallel to each other and provide rotational axes for the hinge arm and the hinge link. The hinge body, hinge cup, hinge arm, and hinge link comprise a four-bar linkage. Hinge link 16 is stamped from a flat sheet. Formed integrally in the hinge link are “hinge eyes” 20 and 22. The hinge eyes are formed typically by rolling the flat sheet about a desired diameter.
As shown in FIG. 1B, pin 18 is seated in hinge eyes 20 and 22 and forms a pivot for the hinge link. Gaps 24 and 26 exist due to clearance required for hinge link 16 to pivot. Gaps 24 and 26 can be seen between hinge link 16 and hinge body 12. Gaps 24 and 26 allow for unwanted movement of hinge link 16 along pin 18 to occur under heavy loads.
As shown in FIG. 1C, in many heavy duty applications the components of the cabinet are subjected to high forces. For example, force 25 in a downward direction parallel to the hinge pins causes deflection of the hinge eyes. In extreme cases, the deflection results in a permanent and cumulative deformation of the hinge eyes. Permanent deformation allows hinge link 16 to disengage from pin 18, causing misalignment of the rotational axes and ultimately hinge failure. In another example, high frequency usage of cabinet components causes repetitive loading and vibration which in turn causes widening of the hinge eyes and eventual hinge failure.
Therefore, a need exists for an easily installed, robust, simple and affordable hinge capable of withstanding excessive loading and excessive force while still delivering precision and durable motion to the cabinet door.